[Arryn]

Originally posted by AStott:
Eh... why bother with all the complicated methods of ensuring the calls happen in the right order. Instead, change:
if penetration+2d6 < MR+2d6

To:
if penetration < MR+2d6-2d6

Since both of the random calls are on the same side of the equation, the defined precendence order will ensure they are called in a consistent manner.

The problem comes in that the compiler's optimization will substitute the same call to the random number function for both die rolls. It won't make the two rand() calls the coders intend. What it does is make one call and plug the same value into both places. The optimizer does not know that in this circumstance, two calls to the same function do not return the same value.